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NATIONAL NCHRP REPORT 669 COOPERATIVE HIGHWAY RESEARCH PROGRAM Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays
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TRANSPORTATION RESEARCH BOARD 2010 EXECUTIVE COMMITTEE* OFFICERS CHAIR: Michael R. Morris, Director of Transportation, North Central Texas Council of Governments, Arlington VICE CHAIR: Neil J. Pedersen, Administrator, Maryland State Highway Administration, Baltimore EXECUTIVE DIRECTOR: Robert E. Skinner, Jr., Transportation Research Board MEMBERS J. Barry Barker, Executive Director, Transit Authority of River City, Louisville, KY Allen D. Biehler, Secretary, Pennsylvania DOT, Harrisburg Larry L. Brown, Sr., Executive Director, Mississippi DOT, Jackson Deborah H. Butler, Executive Vice President, Planning, and CIO, Norfolk Southern Corporation, Norfolk, VA William A.V. Clark, Professor, Department of Geography, University of California, Los Angeles Eugene A. Conti, Jr., Secretary of Transportation, North Carolina DOT, Raleigh Nicholas J. Garber, Henry L. Kinnier Professor, Department of Civil Engineering, and Director, Center for Transportation Studies, University of Virginia, Charlottesville Jeffrey W. Hamiel, Executive Director, Metropolitan Airports Commission, Minneapolis, MN Paula J. Hammond, Secretary, Washington State DOT, Olympia Edward A. (Ned) Helme, President, Center for Clean Air Policy, Washington, DC Adib K. Kanafani, Cahill Professor of Civil Engineering, University of California, Berkeley Susan Martinovich, Director, Nevada DOT, Carson City Debra L. Miller, Secretary, Kansas DOT, Topeka Sandra Rosenbloom, Professor of Planning, University of Arizona, Tucson Tracy L. Rosser, Vice President, Corporate Traffic, Wal-Mart Stores, Inc., Mandeville, LA Steven T. Scalzo, Chief Operating Officer, Marine Resources Group, Seattle, WA Henry G. (Gerry) Schwartz, Jr., Chairman (retired), Jacobs/Sverdrup Civil, Inc., St. Louis, MO Beverly A. Scott, General Manager and Chief Executive Officer, Metropolitan Atlanta Rapid Transit Authority, Atlanta, GA David Seltzer, Principal, Mercator Advisors LLC, Philadelphia, PA Daniel Sperling, Professor of Civil Engineering and Environmental Science and Policy; Director, Institute of Transportation Studies; and Interim Director, Energy Efficiency Center, University of California, Davis Kirk T. Steudle, Director, Michigan DOT, Lansing Douglas W. Stotlar, President and CEO, Con-Way, Inc., Ann Arbor, MI C. Michael Walton, Ernest H. Cockrell Centennial Chair in Engineering, University of Texas, Austin EX OFFICIO MEMBERS Peter H. Appel, Administrator, Research and Innovative Technology Administration, U.S.DOT J. Randolph Babbitt, Administrator, Federal Aviation Administration, U.S.DOT Rebecca M. Brewster, President and COO, American Transportation Research Institute, Smyrna, GA George Bugliarello, President Emeritus and University Professor, Polytechnic Institute of New York University, Brooklyn; Foreign Secretary, National Academy of Engineering, Washington, DC Anne S. Ferro, Administrator, Federal Motor Carrier Safety Administration, U.S.DOT LeRoy Gishi, Chief, Division of Transportation, Bureau of Indian Affairs, U.S. Department of the Interior, Washington, DC Edward R. Hamberger, President and CEO, Association of American Railroads, Washington, DC John C. Horsley, Executive Director, American Association of State Highway and Transportation Officials, Washington, DC David T. Matsuda, Deputy Administrator, Maritime Administration, U.S.DOT Victor M. Mendez, Administrator, Federal Highway Administration, U.S.DOT William W. Millar, President, American Public Transportation Association, Washington, DC Robert J. Papp (Adm., U.S. Coast Guard), Commandant, U.S. Coast Guard, U.S. Department of Homeland Security, Washington, DC Cynthia L. Quarterman, Administrator, Pipeline and Hazardous Materials Safety Administration, U.S.DOT Peter M. Rogoff, Administrator, Federal Transit Administration, U.S.DOT David L. Strickland, Administrator, National Highway Traffic Safety Administration, U.S.DOT Joseph C. Szabo, Administrator, Federal Railroad Administration, U.S.DOT Polly Trottenberg, Assistant Secretary for Transportation Policy, U.S.DOT Robert L. Van Antwerp (Lt. Gen., U.S. Army), Chief of Engineers and Commanding General, U.S. Army Corps of Engineers, Washington, DC *Membership as of July 2010.
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NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM NCHRP REPORT 669 Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays Robert L. Lytton Fang Ling Tsai Sang-Ick Lee Rong Luo Sheng Hu Fujie Zhou TEXAS TRANSPORTATION INSTITUTE TEXAS A&M UNIVERSITY College Station, TX Subscriber Categories Pavements Research sponsored by the American Association of State Highway and Transportation Officials in cooperation with the Federal Highway Administration TRANSPORTATION RESEARCH BOARD WASHINGTON, D.C. 2010 www.TRB.org
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NATIONAL COOPERATIVE HIGHWAY NCHRP REPORT 669 RESEARCH PROGRAM Systematic, well-designed research provides the most effective Project 01-41 approach to the solution of many problems facing highway ISSN 0077-5614 administrators and engineers. Often, highway problems are of local ISBN 978-0-309-15505-2 interest and can best be studied by highway departments individually Library of Congress Control Number 2010936725 or in cooperation with their state universities and others. However, the © 2010 National Academy of Sciences. All rights reserved. accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of COPYRIGHT INFORMATION cooperative research. Authors herein are responsible for the authenticity of their materials and for obtaining In recognition of these needs, the highway administrators of the written permissions from publishers or persons who own the copyright to any previously American Association of State Highway and Transportation Officials published or copyrighted material used herein. initiated in 1962 an objective national highway research program Cooperative Research Programs (CRP) grants permission to reproduce material in this employing modern scientific techniques. This program is supported on publication for classroom and not-for-profit purposes. Permission is given with the understanding that none of the material will be used to imply TRB, AASHTO, FAA, FHWA, a continuing basis by funds from participating member states of the FMCSA, FTA, or Transit Development Corporation endorsement of a particular product, Association and it receives the full cooperation and support of the method, or practice. It is expected that those reproducing the material in this document for Federal Highway Administration, United States Department of educational and not-for-profit uses will give appropriate acknowledgment of the source of any reprinted or reproduced material. For other uses of the material, request permission Transportation. from CRP. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of NOTICE modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which The project that is the subject of this report was a part of the National Cooperative Highway Research Program, conducted by the Transportation Research Board with the approval of authorities on any highway transportation subject may be drawn; it the Governing Board of the National Research Council. possesses avenues of communications and cooperation with federal, The members of the technical panel selected to monitor this project and to review this state and local governmental agencies, universities, and industry; its report were chosen for their special competencies and with regard for appropriate balance. relationship to the National Research Council is an insurance of The report was reviewed by the technical panel and accepted for publication according to procedures established and overseen by the Transportation Research Board and approved objectivity; it maintains a full-time research correlation staff of by the Governing Board of the National Research Council. specialists in highway transportation matters to bring the findings of The opinions and conclusions expressed or implied in this report are those of the research directly to those who are in a position to use them. researchers who performed the research and are not necessarily those of the Transportation The program is developed on the basis of research needs identified Research Board, the National Research Council, or the program sponsors. by chief administrators of the highway and transportation departments The Transportation Research Board of the National Academies, the National Research and by committees of AASHTO. Each year, specific areas of research Council, and the sponsors of the National Cooperative Highway Research Program do not needs to be included in the program are proposed to the National endorse products or manufacturers. Trade or manufacturers' names appear herein solely because they are considered essential to the object of the report. Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs. Published reports of the NATIONAL COOPERATIVE HIGHWAY RESEARCH PROGRAM are available from: Transportation Research Board Business Office 500 Fifth Street, NW Washington, DC 20001 and can be ordered through the Internet at: http://www.national-academies.org/trb/bookstore Printed in the United States of America
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COOPERATIVE RESEARCH PROGRAMS CRP STAFF FOR NCHRP REPORT 669 Christopher W. Jenks, Director, Cooperative Research Programs Crawford F. Jencks, Deputy Director, Cooperative Research Programs Amir N. Hanna, Senior Program Officer Eileen P. Delaney, Director of Publications Margaret B. Hagood, Editor NCHRP PROJECT 01-41 PANEL Field of Design--Area of Pavements Kevin D. Hall, University of Arkansas - Fayetteville, Fayetteville, AR (Chair) Bruce A. Chadbourn, Minnesota DOT, Maplewood, MN Dar-Hao Chen, Texas DOT, Austin, TX Adam J. T. Hand, Granite Construction, Inc., Sparks, NV Abdallah J. Jubran, Georgia DOT, Forest Park, GA Linda M. Pierce, Applied Pavement Technology, Inc., Santa Fe, NM (formerly Washington State DOT) Shakir R. Shatnawi, Shatec Engineering Consultants LLC, El Dorado Hills, CA (formerly California DOT) Timothy E. Smith, Maryland State Highway Administration, Hanover, MD Nelson H. Gibson, FHWA Liaison Stephen F. Maher, TRB Liaison
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FOREWORD By Amir N. Hanna Staff Officer Transportation Research Board This report presents mechanistic-based models for predicting the extent and severity of reflection cracking in hot-mix asphalt (HMA) overlays. These models were developed for use in the design and analysis of HMA overlays; they can be incorporated into the AASHTO Mechanistic-Empirical Pavement Design Guide (MEPDG) software. The report and accom- panying software will guide pavement and construction engineers in identifying and spec- ifying HMA overlays for asphalt and concrete pavements that will provide desired service life and performance. The information contained in the report will be of immediate inter- est to state pavement engineers and others concerned with the design and rehabilitation of asphalt and concrete pavements. Reflection cracking is one of the primary forms of distress in HMA overlays of flexible and rigid pavements. In addition to affecting ride quality, the penetration of water and foreign debris into these cracks accelerates the deterioration of the overlay and the underlying pave- ment, thus reducing service life. The basic mechanism causing reflection cracking is strain concentration in the overlay due to movement in the existing pavement in the vicinity of joints and cracks. This movement may be induced by bending or shearing action resulting from traf- fic loads or temperature changes and is influenced by traffic volume and characteristics, daily and seasonal temperature variations, and other factors (e.g., pavement structure and condi- tion, HMA mixture properties, the degree of load transfer at joints and cracks). Preliminary models for predicting the extent and severity of reflection cracking in HMA overlays have been developed; however, only limited research has been performed to evaluate and validate these models. Thus, research was needed to address the issues associated with reflection cracking and to develop mechanistic-based models that account for the effects of reflection cracking on performance for use in mechanistic-empirical procedures for the analysis and design of HMA overlays. Under NCHRP Project 1-41, "Models for Predicting Reflection Cracking of Hot-Mix Asphalt Overlays," Texas A&M Research Foundation of College Station, Texas worked with the objective of identifying or developing mechanistic-based models for predicting reflection cracking in HMA overlays of flexible and rigid pavements and associated computational soft- ware for use in mechanistic-empirical procedures for overlay design and analysis. To accom- plish this objective, the research reviewed available information relevant to reflection crack- ing of HMA overlays, considered the factors that contribute to reflection cracking, evaluated available models, and developed mechanistic-based models for predicting the extent and severity of reflection cracking in HMA overlays. In addition, the research developed software, compatible with the MEPDG software, to facilitate use of these models for (1) the design and
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analysis of HMA overlays or (2) developing calibration coefficients and enhanced models for specific types of overlays and climatic conditions. The models developed in this research will be particularly useful to highway agencies because they allow consideration of reflection cracking in the design of HMA overlays and selection of overlays for asphalt and concrete pavements that are expected to yield economic and other benefits. The incorporation of these models into the AASHTO MEPDG will help account for the effects of reflection cracking on performance thus improving the analysis and design of HMA overlays of flexible and rigid pavements. Appendixes A through T contained in the research agency's final report provide detailed information on the different aspects of the research, including user guides to support the software. These appendixes are not published herein but they are available on the NCHRP Report 669 summary web page at http://www.trb.org/Main/Blurbs/163988.aspx.
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CONTENTS 1 Chapter 1 Introduction and Research Approach 1 Introduction 1 Objective 1 Scope 1 Organization of the Report 2 Research Approach 2 Material Properties 3 Traffic 3 Crack Growth and Pavement Temperature 3 Computational Efficiency 3 Calibration to Field Data 4 Use in Design 5 Chapter 2 Findings 5 Introduction 5 Reflection Cracking Definition and Mechanisms 5 Available Reflection Cracking Models 6 Selection of a Reflection Cracking Model 7 Process of Constructing a Calibrated Reflection Cracking Model 8 Overlay Sections with Sufficient Data for Model Development 8 Collection of Pavement Structure Data 10 Pavement Distress Data Collection 10 Traffic Data Collection 11 Categorization of Traffic Loads 11 Classification of Vehicles 11 Axle Load Distribution Factor 13 Categorizing Traffic Load 14 Climatic Data Collection 14 Finite Element Method for Calculating SIF 17 Method of Predicting SIF 19 Traffic Loads and Tire Footprints 19 Tire Patch Length 19 Determination of the Effect of Cumulative Axle Load Distribution on Tire Length 19 Modeling of Cumulative Axle Load Distribution 20 Determination of Hourly Number of Axles 20 Probability Density on Tire Patch Length 26 Reflection Cracking Amount and Severity Model 27 Calibration of Field Reflection Cracking Model 28 System Identification Process 29 Parameter Adjustment and Adaption Algorithm 30 Calibrating Reflection Cracking Model of Test Sections
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33 Prediction of Temperature in a HMA Overlay 33 Heat Transfer in Pavement 34 The Surface Boundary Condition 34 The Bottom Boundary Condition 35 Numerical Solution of the Model 35 Obtaining Hourly Climatic Input Data 35 Stiffness, Tensile Strength, Compliance, and Fracture Properties of Mixtures 36 Artificial Neural Network Algorithms for Witczak's Complex Modulus Models 38 Models of Tensile Strength of Mixtures 38 Models of Paris and Erdogan's Law Fracture Coefficients A and n 39 Healing Coefficients 39 Stress Wave Pattern Correction for Viscoelastic Crack Growth 39 Computational Method for Crack Growth Due to Traffic 41 Computational Method for Viscoelastic Thermal Stresses 42 Supervisory Program to Compute Crack Growth 42 User Interface Program for Input and Output Data 42 Computation-to-Field Calibration Coefficients 44 Validation of the Calibration Coefficients 48 Chapter 3 Interpretations, Appraisal, and Applications 48 Introduction 48 The Model Development Process 48 Mechanistic Prediction of Crack Growth 49 HMA Overlay Material Properties 49 Weather Data and Temperature Prediction 49 Consistent Description of Reflection Cracking Distress 49 Calibration of Calculated Overlay Life to the Observed Distress 50 Calibrated Results Compared with Observed Field Data 50 Calibration Coefficients by Regression Analysis 50 Predictions of Overlay Reflection Cracking 55 Calibration of the Computational Model to Field Data 56 Chapter 4 Summary and Suggested Research 56 Summary 56 Suggested Research 58 References 60 Appendices
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AUTHOR ACKNOWLEDGMENTS The research reported herein was performed under NCHRP Project 1-41 by the Texas Transportation Institute of the Texas A&M University. Robert L. Lytton, Professor of Civil Engineering, was the princi- pal investigator and the co-principal investigator was Fujie Zhou, Research Engineer. The other authors of this report are Fang Ling Tsai and Sang-Ick Lee, both Research Assistants and Sheng Hu and Rong Luo, both Post-Doctoral Research Associates. The research work was materially aided by the assistance given by Jagannath Mallela and Harold L. von Quintus of the Applied Research Associates, Inc. (ARA), who provided information and data on the New York City overlay test sections. Permission to use that data was given by the City of New York, Depart- ment of Design and Construction, Division of Infrastructure. The Texas overlay test section data used in the project were provided by Joe W. Button and Arif Chowdhury of the Texas Transportation Institute with the approval of German Claros, Research Coordinator with the Texas Department of Transporta- tion. The extraction of data and categorization of overlay sections from the Long-Term Pavement Per- formance database was done by Thomas Freeman of the Texas Transportation Institute. The two pro- grams produced in the project are written in the C# language as was suggested by Gregg Larson of ARA and supported by Vicki Schofield of AASHTO. All subprograms which were not originally in that lan- guage were re-written by Sheng Hu of the Texas Transportation Institute. The Artificial Neural Network models of the mixture moduli and the stress intensity factors were provided under a subcontract by Halil Ceylan of Iowa State University. Helpful advice and direction on the use of weather databases was given by Gregg Larson of ARA. The temperature prediction model used in both the design and calibration pro- grams and its description was provided by Charles J. Glover, Professor of Chemical Engineering, Texas A&M University and by Research Assistants Rongbin Han and Xin Jin, both of the Chemical Engineer- ing Department of Texas A&M University. The thermal stress prediction program was provided by Rey- naldo Roque of the University of Florida in Gainesville. The finite element program which generated the stress intensity factors which were modeled with the Artificial Neural Network algorithms was written by Sheng Hu, description of that model was written by Sheng Hu, Xiaodi Hu, and Lubinda Walubita, all Post-Doctoral Research Associates and by Fujie Zhou, Research Engineer with the Texas Transportation Institute. The review and evaluation of available reflection cracking models was written by Fujie Zhou. Cathy Bryan of the Texas Transportation Institute was responsible for the final manuscript preparation.